Injection devices are known with a cartridge that contain a medicament to be injected. The cartridges of traditional devices typically have a seal at one end that is pierced by a proximal side of a needle to open a fluid pathway from the cartridge to the needle.
For example, U.S. Pat. No. 3,375,825 discloses a prefilled syringe. A rear penetrating end of a hypodermic needle penetrates a diaphragm to expose the contents of the barrel of the syringe for injection when the needle is attached to the barrel. Similarly, U.S. Pat. No. 2,645,223 discloses a jet injection device with a cannula that has a pointed inner end that penetrates a stopper in an ampule.
U.S. Pat. No. 3,811,441 teaches an ampule with a pierceable seal. The ampule is moved against a cannula, which pierces the seal prior to injection to communicate the medicament in the ampule and the outside by way of the cannula. U.S. Pat. No. 5,137,528 describes a local-anesthetic ampule that is placed in the barrel of a hypodermic syringe. The user manually advances the ampule in the barrel towards a proximal end of the hypodermic needle of the syringe, causing this needle end to perforate a rubber diaphragm of the ampule to enable injection of the anesthetic.
Syringes are also known for mixing a liquid and a medicament that are held in different compartments. U.S. Pat. No. 4,874,381, for example, shows a hypodermic syringe with two compartments: one with a liquid phase and the other with a solid phase, which are to be mixed to form a solution prior to injection. The syringe has a first piston to displace the liquid and solution for the injection. A second piston is located between the two compartments. A bypass interconnects the two compartments when the second piston is shifted to allow the two ends of the bypass to open to opposite sides of the piston.
U.S. Pat. Nos. 6,132,395; 6,264,629; and 6,471,669 disclose needless injection apparatuses with plugs that are moved out of a cartridge when the apparatuses are assembled into a configuration that enables a subsequent injection, by an additional action by the user.
Injection devices that employ a portion of a cartridge that is pieced by a proximal side of a needle to open the cartridge typically demand high precision in manufacture and alignment of the parts to ensure that the needle pierces the cartridge properly to allow the flow of the substance through the needle. There is a need for an injection device with a sealed cartridge that can be opened reliably without requiring the puncture thereof of the cartridge to open it and which can be opened at the time the injector is fired.